Students wave goodbye to Broncos receiver Eddie Royal on Tuesday during a fourth-grade gym class at Fairmount Elementary in Golden. Royal led the kids in fitness activities as part of the NFL's PLAY 60 campaign, which aims to help youth get 60 minutes of exercise a day.

When the Broncos’ defense takes on Kansas City’s offense Sunday, it will feature two units meeting for the first time this season.

Say what? Yes, the Chiefs beat the Broncos 33-19 on Sept. 28 at Arrowhead Stadium. But since that game, the Broncos are playing a new defense, and the Chiefs are employing a new offense.

In getting embarrassed by previously winless Kansas City in Week 4, the Broncos were playing a 3-4 alignment. Since their bye week after their seventh game, the Broncos have exclusively played their more familiar 4-3 defense.

The Broncos’ defense has noticeably improved, particularly against the run. After allowing 5.4 yards per rush through seven games, the Broncos have surrendered a respectable 4.2 yards in the five games since. The past five opponents have averaged 129.8 rushing yards, compared with 154.6 yards in the first seven games.

“We got all these injuries, people saying we’re playing with guys off the street, but hey, we’re all football players and through preparation and dedication, anything is possible,” Broncos cornerback Dre Bly said.

Broncos coach Mike Shanahan said it was an adjustment to practice, as well as the system, that created the improvement.

“We put our pads back on Wednesday and Thursday and we made sure that everybody knew what they were going to do,” Shanahan said. “You can see it when you have pads on. Obviously, the downside to that is you can get more people hurt. I thought we had lost so many players at that time that it didn’t matter. We had to get better.”

The Chiefs’ offense, meanwhile, played a power running game offense against the Broncos, rarely passing except on third down. Chiefs running back Larry Johnson took off on a 65-yard run on the game’s second play against the Broncos’ 3-4 and finished with 198 yards and two touchdowns.

The Chiefs are playing a spread offense now with quarterback Tyler Thigpen averaging 32.2 pass attempts in the past six games.

Roster move.

The Broncos officially placed defensive tackle Josh Shaw on the season-ending injured reserve list Tuesday after he suffered a dislocated elbow Sunday against the New York Jets.

Shaw will be replaced in the game-day front-four rotation by Nic Clemons. As for the roster spot, the Broncos could promote one of their two defensive linemen from their practice squad: tackle Matthias Askew or end Ryan McBean.

Footnotes.

The Broncos have three nominees for weekly honors: Shanahan for coach of the week, Jay Cutler for player of the week and Peyton Hillis for top rookie. . . . Thigpen also loves to run off the spread, as he leads all NFL quarterbacks with 251 yards rushing. Not bad, considering he didn’t play in two games, including the victory against Denver, and played less than a half in two others. . . . When Thigpen passes, he usually looks for Tony Gonzalez, who leads all NFL tight ends with 806 yards receiving, nearly 100 more than runner-up Jason Witten. . . . Anytime the Broncos and Chiefs get together, it’s rookies galore. The Chiefs lead the NFL with 10 rookies who have played at least 10 games. The Broncos are second with nine rookies who have played in 10. . . . Quietly — and long snappers would have it no other way — Mike Leach played in his 100th consecutive game for the Broncos against the Jets. . . . The Broncos-Jets game will be reshown in a condensed, 90-minute form at 6 p.m. today on the NFL Network.

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